1. Field of the Invention
The present invention relates to a semiconductor optical integrated device.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2007-294914 discloses an optical semiconductor device having a structure configured to efficiently transfer heat from a heater to an optical waveguide layer. The optical semiconductor device includes a semiconductor substrate, a stripe-shaped semiconductor region having an upper surface and a side surface, and the heater. In the optical semiconductor device, the semiconductor substrate has a larger width than the width of the semiconductor region. The optical waveguide layer is arranged in the semiconductor region. The heater is arranged above the optical waveguide layer.
Japanese Unexamined Patent Application Publication No. 2007-273644 discloses an optical semiconductor device having a structure configured to efficiently heat an optical waveguide by a heater. The optical semiconductor device includes a semiconductor substrate, an optical semiconductor region, and the heater arranged on the optical semiconductor region. The optical semiconductor region is arranged on the semiconductor substrate and has a smaller width than the width of the semiconductor substrate. The optical semiconductor region further includes a cladding region, an optical waveguide layer, and a low thermal conductivity layer. The optical waveguide layer is arranged in the cladding region and has a higher refractive index than that of the cladding region. The low thermal conductivity layer is arranged between the optical waveguide layer and the semiconductor substrate and has a lower thermal conductivity than that of the cladding region. The low thermal conductivity layer is composed of InGaAsP, InAlGaAs, or InAlAsP.
Japanese Unexamined Patent Application Publication No. 2007-273694 discloses an optical semiconductor device having a structure configured to efficiently transfer heat from a heater to an optical waveguide. The optical semiconductor device includes an optical waveguide region having an optical waveguide layer with a diffraction grating, a heater arranged on the optical waveguide region, an electrode arranged in the vicinity of the heater, and a lead that connects the electrode and the heater. Grooves along a waveguiding direction are formed on both sides of the optical waveguide region. The lead spans the grooves.
Japanese Unexamined Patent Application Publication No. 2007-273650 discloses an optical semiconductor device having a structure configured to allow a heater to generate sufficient heat even at supplying a low voltage to the heater and configured to reduce the heat radiation from an electrode. The optical semiconductor device includes a semiconductor region having an optical waveguide and the heater arranged on the semiconductor region. A power-supplying lead line is configured to connect the electrode arranged on the heater to a wire-bonding pad. The power-supplying lead line and a ground lead line are alternately arranged in a direction along the optical waveguide.